Four hundred and fifty seven Italian patients with liver cirrhosis--140 with hepatocellular carcinoma (HCC) and 317 without HCC (CP)--were studied in order to assess the risk factors of HCC in cirrhotic patients in Italy and, particularly, the role of HBV infection, that seems to be important in high and not in low incidence areas of HBV infection. All HCC were histologically confirmed and all cirrhotic patients were followed-up for one year or more without evidence of HCC. The statistical analysis was carried out by means of Stepwise Logistic Regression. Increasing age, male sex and HBV infection were found to be significant risk factors of HCC in CP, in a medium-incidence area of HCC and HBV as in Italy. There is, therefore, a striking correlation between HBV and the geographical incidence of HCC. In general, the higher the incidence of HBV, the greater its importance as a risk factor of HCC.